Ultrafiltration and absorption characteristics of hydroxyethylstarch and dextran during long dwell peritoneal dialysis exchanges in rats.

Glucose has several disadvantages such as low pH, high osmolality and hyperglycemia. Rapid glucose absorption contributes to hyperlipidemia, obesity and ultrafiltration failure in peritoneal dialysis patients. Two commercially available plasma substitutes 10% hydroxyethylstarch (HES) and 6% dextran were studied for ultrafiltration and absorption patterns. 18 ml of each solution were instilled into the peritoneal cavity of 6 non-uremic rats. HES yielded a significantly (p less than 0.02) greater ultrafiltration after 6 h of dwell, whereas 2.3% glucose solution showed the typical ultrafiltration pattern of an easily absorbable osmotic agent. With 6% dextran ultrafiltration was markedly lower. At the end of cycle time the mean absorption rates for HES were 62.7% and 41.5% for dextran. It is concluded that HES is a potent osmotic agent due to sustained colloidal ultrafiltration. However, despite their high molecular weights both solutions were markedly absorbed probably by lymphatics. However, accumulation in tissues and undefined metabolic pathways might prove disadvantageous in patients with ESRD.